Just adding some useful evidence showing the speeds NASA claims. A quick search landed me on NASA's page where they give the following speed information about "The Orbiter": "After the solid rockets are jettisoned, the main engines provide thrust which accelerates the Shuttle from 4,828 kilometers per hour (3,000 mph) to over 27,358 kilometers per hour (17,000 mph) in just six minutes to reach orbit. They create a combined maximum thrust of more than 1.2 million pounds." Google says 3000 mph is mach 3.91 . 17000 mph is mach 22.16. Here is the link to NASA's page: https://www.nasa.gov/reference/the-space-shuttle/#:~:text=After%20the%20solid%20rockets%20are,more%20than%201.2%20million%20pounds.